【数据存储】行会基金：公共资金的收支与对账

---基金的收入：税收与捐献双渠道
function GuildFund.income(gid, amount, source)
    local fund = GuildFund.books[gid]
    fund.balance = fund.balance + amount
    fund.flows[#fund.flows + 1] = {
        dir = "in", amount = amount,
        source = source, at = os.time(),
    }
    -- 流水的滚动保留 90 天
    if #fund.flows > 5000 then
        GuildFund.archive(gid)
    end
end

---攻城税收的自动入账
function GuildFund.taxIncome(gid, taxAmount)
    GuildFund.income(gid, taxAmount, "sabak_tax")
    sendmsg(nil, 1, "「" .. Guild.nameOf(gid) ..
        "」今日收取沙巴克税收 " .. taxAmount .. " 金币")
end

---基金的支出：双签的审批
function GuildFund.spend(gid, actor, amount, purpose)
    local pos = getplayguildlevel(actor)
    if pos ~= 0 then
        sendmsg(actor, 1, "仅会长可发起支出")
        return false
    end
    local fund = GuildFund.books[gid]
    if fund.balance < amount then
        sendmsg(actor, 1, "基金余额不足")
        return false
    end
    -- 双签：支出需副会长确认
    if not GuildFund.secondSign(gid, actor, amount) then
        sendmsg(actor, 1, "支出已发起，待副会长确认")
        return false
    end
    fund.balance = fund.balance - amount
    fund.flows[#fund.flows + 1] = {
        dir = "out", amount = amount,
        source = purpose, at = os.time(),
    }
    sendmsg(nil, 1, "「" .. Guild.nameOf(gid) ..
        "」支出 " .. amount .. " 金币：" .. purpose)
    return true
end